Goals: Intended to impact the surface of Venus, this spacecraft -- also known as Sputnik 20 -- was the second of three attempts by the Soviet Union in 1962 to reach the planet.

Accomplishments: None. Like its predecessor, the failure of a booster rocket kept it from leaving Earth orbit. This time, the rocket didn't fire at all. The spacecraft remained stranded in Earth orbit for five days and then re-entered the atmosphere.